copperdesk on "Select Menu at the front end"

Hello,

I have 3 level of pages.

Parent Page
- child page
-- grandchild page

• I want create a front end select menu where user can chose the "parent page".
• A second select menu should appear showing "child pages" depending on the selected "parent page".
• A third menu should appear showing "grandchild pages" depending on selected "child page".

Is this even possible? I'm clueless. I've tried http://codex.wordpress.org/Function_Reference/wp_dropdown_pages#Examples but it works only for the first page.

<form action="<?php bloginfo('url'); ?>" method="get">
   <?php wp_dropdown_pages(); ?>
   <input type="submit" name="submit" value="view" />
   </form>

I would really appreciate if anyone take few minutes and show me the right direction. I will very grateful.

Thank you in advance.